Wednesday, November 30, 2011

On Crohn's disease and the patent case being heard next week in the Supreme Court

Next week the United States Supreme Court will hear argument in a patent case styled Mayo Collaborative Services v. Prometheus Laboratories, Inc., for which the SCOTUSblog has this link to the many briefs.

The patents at issue involve blood testing after administration of a drug called azathioprine, which I have taken off and on for some years. Azathioprine is an immune suppressant used as an anti-rejection drug for people who receive organ transplants. It is also prescribed for Crohn's disease and ulcerative colitis, which are thought to be disorders of the immune system.

It is an alarming thing to sit and read the label as I used to do sometimes and think about whether you want to take that pill. Some people who take azathioprine for Crohn's disease get one form of cancer or another and die. For some patients, it works no better than placebos on their moderate to severe Crohn's disease. The challenge with this powerful medicine is how to figure out how to give enough without giving too much to achieve the good effects and avoid the bad. Not everyone requires the same dosage to achieve the same level of metabolites in their blood.

A group of researchers "developed a database of pediatric patients withinflammatory bowel disease who had received thiopurine treatment," applied standard laboratory techniques to measure the thiopurine metabolite levels in their blood, and observed some correlations between particular values and whether the patients did better or worse. The appellee Prometheus learned of this research, licensed it from the inventors and the hospital for whom they worked, filed patent applications, and marketed a blood test product that would measure whether the metabolite levels for GI patients taking azathioprine were within the optimal range of values.

The Mayo Clinic used this product for years, then decided that it could make and sell its own product to do a better job of evaluating thiopurine metabolite levels. Prometheus sued for patent infringement, and the case made its way to the high court.

The question presented, according to the appellant Mayo, is:

"Whether 35 U.S.C. § 101 is satisfied by a patent claim that covers observed correlations between blood test results and patient health, so that the patent effectively preempts use of the naturally occurring correlations, simply because well-known methods used to administer prescription drugs and test blood may involve 'transformations' of body chemistry."

In other words, the Court will decide whether Prometheus can patent what amounts to nothing more than a lab test to see whether the level of thiopurine metabolites is within the range of therapeutic values shown by the research.

On the face of it, the patent seems preposterous. When only ordinary testing techniques are involved, why should any company be able to claim exclusive ownership of the idea of testing for any level of some chemicals in the blood, based on research that shows some particular level is best for patient health? Yet such patents are evidently common, and defended as Prometheus sought to do in its brief, as necessary to fund the type of research that lead to the conclusions about the therapeutic levels of the thiopurine metabolites - even though the specific research in this case was not done for commercial purposes.